• Journal of Broadcast Engineering
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• v.21 no.1
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• pp.24-35
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• 2016

By estimating environment light distribution, we can generate realistic shadow images in AR(augmented reality). When we estimate light distribution without sensing equipment, environment light model, geometry of virtual object, and surface reflection property are needed. Previous study using 3D marker builds surrounding light environment with a geodesic dome model and analyzes shadow images. Because this method employs candidate shadow maps in initial scene setup, however, it is difficult to estimate precise light information. This paper presents a novel light estimation method based on hierarchical light distribution model subdivision. By using an overlapping area ratio of the segmented shadow and candidate shadow map, we can make hierarchical subdivision of light geodesic dome.

• Transactions of the Korean hydrogen and new energy society
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• v.17 no.3
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• pp.347-352
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• 2006

분자전해질연료전지 내의 다공성 기체확산층은 반응가스의 확산과 전자이동통로의 역할을 수행할 뿐만 아니라 전기화학반응에 의해 공기극에서 생성된 수분(기상 혹은 액상)을 반응면으로부터 분리판 채널 방향으로 이동시켜 배출시키는 중요한 역할을 한다. 따라서 물관리를 통한 성능향상을 위해서는 기체 확산층의 구조 및 재료특성에 대한 심도 릴은 연구가 필요하다. 실제 단위전지 체결시 기체확산층은 분리판의 리브(rib)에 의해 눌리게 되며, 그 부분의 기공 크기 분포의 변화를 야기한다. 또한 리브 전단부분에서 탄소 섬유가 손상을 입으며, 탄소 섬유를 감싸고 있는 PTFE coating이 벗겨지게 되어 표면화학적 특성이 달라진다. 본 연구에서는 단위전지 체결 시 분리판에 의해 눌리는 기체확산층의 기공 크기 분포 변화를 측정하였으며, 기공의 소수성에서 친수성으로의 변화를 알아보았다. Mercury 기공 측정기와 PMI 기공 측정기는 큰 기공 분포의 변화에, 질소의 흡/탈착을 이용한 BET 방식은 작은 크기의 기공 분포 변화 관찰에 사용되었다. 체결압에 의한 탄소섬유의 구조적 변화와 아울러 표면의 습윤 정도의 변화를 XPS와 물/알콜 Uptake를 이용해 알아보았다. 이 연구를 바탕으로 물관리를 통한 연료전지 성능 향상을 위한 최적 GDL 선정에 기반이 되는 자료를 도출하였다.

• Korean Journal of Weed Science
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• v.31 no.1
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• pp.24-33
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• 2011

Wingstem, Verbesina alternifolia of North America origin, was introduced in 1981 into the Korea terrestrial ecosystem. It scattered in a number of places with limited population size in most cases. Its population has spread into the forest at the Chiaksan National Park and occupied the natural vegetation. Distributions of wingstem were the most popular along the 12 road sites, especially in Route 453, Seohwa-myeon, Inje-gun, Gangwon-do and in Route 31, Yeongyang-gun, Gyeongsangbuk-do with 60% coverage of wingstem. It was also distributed in the 5 forest sites and 5 riversides. Despite of its attractive yellow flower, it is recommended to limit cultivation in the nature reserve or other ecosystem of conservation value.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.04a
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• pp.65-65
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• 2019

비무장지대(DMZ)는 군사적 활동 외에 일반인에 의한 접근이 엄격히 통제되어 자연적으로 생물들이 보호되어 왔으며, 한반도의 거대한 동 서 생태축으로서 그 중요성이 매우 높다. 본 연구는 경기도 연천군지역의 비무장지대 및 민통선지역에 분포하는 자원식물의 현황을 파악하고 희귀식물, 한국특산식물 등 주요 유용자원식물의 보전과 관리에 기초자료를 제공하고자 실시하였다. 연구대상지에 분포하는 자원식물은 74과 168속 192종 4아종 26변종 5품종으로 총 227분류군으로 우리나라에 분포하는 관속식물 4,881(국립수목원, 2007)분류군의 4.66%로 나타났다. 각 과별 구성종의 출현비율을 살펴보면 국화과 36분류군으로 가장 다양하게 출현하였다. 연구대상지내에 분포하는 희귀식물은 쥐방울덩굴(Aristolochia contorta Bunge)로 1분류군이 확인되었으며, 한국특산식물은 키버들(Salix koriyanagi Kimura), 병꽃나무(Weigela subsessilis (Nakai) L.H.Bailey), 은사시나무(Populus tomentiglandulosa T. B. Lee)로 3분류군, 귀화식물은 단풍잎돼지풀(Ambrosia trifida L.), 족제비싸리(Amorpha fruticosa L.), 아까시나무(Robinia pseudoacacia L.) 등 등 17분류군으로 나타났다. 연구결과 전체적으로 다양한 식물종이 확인되지는 않았으며, 일부 구간에는 가시박(Sicyos angulatus L.), 돼지풀(Ambrosia artemisiifolia L.), 단풍잎돼지풀(Ambrosia trifida L.) 등 생태계교란 야생식물이 폭넓게 분포하고 있는 것을 확인할 수 있었다.

• Korean Journal of Environment and Ecology
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• v.17 no.1
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• pp.9-17
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• 2003

To investigate the structure and the conservation strategy of Nature Ecosystem Preservation Area, 65 plots(10m$\times$10m) set up with random sampling method were surveyed. five group -Larix leptolepis Community, Quercus mongolica-Fraxinus rhynchophylla Community, Fraxinus rhynchophylla-Quercus mongolica community. Quercus mongolica-Acer pseudo-sieboldianum community, Quercus mongolica community were classified by cluster analysis. High positive correlations was proved between Quercus mongolica and Sorbus of alnifolia, Acer Mono, Lonicera praeflorens, Sorbus commixta ; Acer mono and Lonicera praeflorens, Sorbus commixta ; Maackia amurensis and Acer triflorum ; Fraxinus rhynchophylla and Betula davurica ; Lonicera praeflorens and Cornus controversa, Sorbus commixta ; Acer triflorum and Rhamnus toshinoi ; Pyrus ussuriensis and Prunus padus ; Cornuscontroversa, and Sorbus commixta, and high negative corrlations was proved between Quercus mongolica and Larix leptolepis, Carpinus cordata ; Tilia amurensis and Larix leptolepis, Morus bombycis. Species diversity(H' ) of investigated groups were ranged 0.4443~1.2036.

• Journal of Energy Engineering
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• v.7 no.2
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• pp.209-215
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• 1998

This paper investigated the vertical throughflow effects on natural convection due to heating from below in horizontal porous layer. The motion of the fluid in the porous layer is governed by Brinkman-Darcy equation. And compared Critical Rayleigh number in case of throughflow with no throughflow. Investigated Nusslet number, isothermalline and flow with the variation of the strength of throughflow in a constant Rayleigh number. In the numerical analysis, flow is assumed to be two-dimensional and unsteady. The numerical scheme used is a finite-difference method. In the experimental study, Temperature distribution was measured by use of Liquid Crystal film. As a results, indicated that throughflow influences largely on the temperature field and as the strength of throughflow increased, unstability of natural convection decreased. Also it could predict the strength of natural convection with the measured Nusselt number.

• Journal of Korean Society for Geospatial Information Science
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• v.10 no.2 s.20
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• pp.39-47
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• 2002

For the purpose of data construction for the systematic management and sight-seeing guidance of the natural park, the Kumoh Mt. Province Park was selected as a pilot area. Digital topographic maps, thematic maps and satellite imagery covering the object area were processed and then landform analysis for elevation, slope, aspect and so on was conducted through DEM generation, and the landcover map and NDVI maP were extracted from Landsat TM data. The database was then constructed with these spatial data for GSIS. The image map was generated from IKONOS satellite data, which cover the pilot area data, with one meter resolution and also 3D visualization which was overlaid with main paths up a mountain were conducted. And the moving image files were produced along main paths up including main natural spectacular sights, cultural assets and management facilities. It is expected that the research result can be utilized as the fundamental data for re-assessing suitable land use and constructing Web-based guidance system.

• Geotechnical Engineering
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• v.7 no.2
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• pp.51-66
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• 1991

In the stability analysis of hillside slopes, the roots of vegetation have been considered to act as a soil reinforcement. In order to predict the amount of increase in soil shear resistance, produced by tensile strength of roots that intersect a potential slip surface in hillside slopes, new soil -root interaction models are proposed in this paper. For this purpose, firstly, laboratary teats and in-situ tests wert performed on soil-root systems, and experimental results were compared with a couple of soil-root interaction models which had been proposed by Gray, Waldron, and Wu etc. Based on this comparison, a new soil-root interaction model is proposed. Secondly, a probabilistic soil-root model is proposed based on statistical analysis considering random nature of root distribution, root characteristics, and soil-root interactions. Finally, to examine the effect of this root reinforcement system on stability of hillside slopes, a simple three-dimensional stability analysis was performed, and it was shown that root reinforcement had a significant stabilizing influence on shallow slips rather than deep slips in hillside slopes.

• Journal of the Korean Geographical Society
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• v.51 no.1
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• pp.127-142
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• 2016

This paper analyzes on the physical place name of Mt. Seoraksan in Joseon period from the historical geographical perspective. The analysis materials are Jirijis, old maps and travel records of Joseon period. The results are as follows. The space range of Mt. Seoraksan in Joseon period and today was different. Mt. Seoraksan in Joseon period was around Daecheongbong Peak nowadays, Ulsanbawi Rock was Mt. Cheonhusan, and north mountain range of Hangyeryeong Pass called Mt. Hangyesan. Region of Mt. Seoraksan and Mt. Hangyesan were devided in Joseon Period. Mt. Seoraksan name was representative in late Joseon period including Mt. Hangyesan and Mt. Cheonhusan. Mountain names were the most in the physical place name. The old name of Hangyeryeong Pass was Osaek Pass in maps of Joseon Period. The popular travel course of Mt. Seoraksan in Joseon period was Baekdamsa Temple-Oseam Temple-Sinheungsa Temple.

• Journal of Korean Society for Geospatial Information Science
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• v.15 no.4
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• pp.11-20
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• 2007

Most natural disasters in Korea are caused by meteorological natural phenomena, which include storms, heavy rains, heavy snow, hail, tidal waves, and earthquakes. Rainfall is the most frequent cause of disasters and accounts for about 80% of all disasters. Particularly in recent years, Korea has seen annual occurrences of natural disasters associated with landslides (slope and retaining wall collapse and burying) due to meteorological causes from the increasing intensity of heavy rains including local heavy rainfalls. In Korea, it is critical to analyze the characteristics of landslides according to rainfall characteristics and to take necessary and proper measures for them. This study assessed the possibility of landslides in the Gangwon region with a geographic information system by taking into account the inducer factors of landslides and the maximum continuous rainfall of each area. It also analyzed areas susceptible to landslides and checked the distribution of landslide-prone areas by considering the rainfall characteristics of those areas.